Good Evening, I did this several years ago and it worked out well. I did not use a slide in. I used a bumper pull TT it made it easy with the side door access. I torched the tongue off took the axels out and then trimmed the wheel wells out with sheet metal and painted same color as factory paint on TT. The Gooseneck trailer was 38' long and the TT was 18' long after cutting the tongue and rear bumper off. That left me a lot of room for the rear area. When looking at GN be carefull there is a lot of junk out there.
"Yeah Our Government Is Honest, Just Ask An American Indian"